Preparation of polymers of polyisocyanates and polyurethane polymers using diazabicyclo-ocatane and aldehydes as co-catalysts



United States Patent 3179 626 PREPARATION OF PiJLiMERS 0F POLYISOCY- ANATES AND POLYURETHANE POLYMERS USING DIAZABICYCLO-OCTANE AND ALDE- 3,179,626 Patented Apr. 20, 1965 diisocyanate-hydroxy mixtures, causing them to polymerize and/or condense rapidly to polyurethanes. The simultaneous catalysis of the two processes in the presence of diisocyanates and polyols permits the rapid formation 5 of polyisocyanates, polyurethanes, or copolymers of polyggy}? g ifi Pa assign to Air isocyanates and polyurethanes in various ratios to produce Products Chemicals Inc. a corporation Delaware new ar 1 unusual compositions varying from resinous hard No Drawing. Filed Jan. 17, 1961, Ser. No. 83,135 solids to fie lble elastomers.

3 Claims. (Cl. 260-775) It has been recognized heretofore that aldehydes are active in effecting cross-linking of curing of polyure- This invention is directed to new catalysts and catalyst thanes. This has generally been effected by treating a combinations effective in forming polyisocyanates and reformed polyurethane with an active aldehyde, such polyurethanes. as form-aldehyde. Thus, DombrowPolyurethane The catalytic activity of certain tertiary amines in (Reinhold, 1957) at page 116 describing Vulcaprene A effecting the formation of polyurethane elastomers or states that: In curing, formaldehyde may be used to foams by interaction of diisocyanates and polyols is well cross-link the amide linkages. Similarly, in US. 2,921,- recognized in the polyurethane art. A particularly efiec- 860 finished polyurethane foam is treated with formtive and unique tertiary amine in this category is 1.4- aldehyde, ketene, etc. to improve the color stability of diazabicyclo-(2,2,2)-octane (hereinafter called diazapolyurethanes. bicycle-octane) as disclosed in US. 2,939,851. It has In contrast to this, in the process of this invention the also been recognized that certain basic compounds, incatalyst combination comprises an active tertiary amine, eluding tertiary amines, such as pyridine, triethylarnine such as 1,4-diazabicyclo-(2,2,2)-octane used in conjuncand N-methyl morpholine, exert a mild catalytic efi'ect tion with an aldehyde, which may also be an aldehyde in the polymerization of organic isocyanates. Since isopolymer. This catalyst combination effects accelerated cyanate polymerization is ordinarily a very slow reaction polymerization of isocyanates and urethanes together With relative to the rapid formation of urethanes, isocyanate a rapid and spontaneous curing of the polymer, all with polymerization and the polymers formed have played little the liberation of heat. The entire reaction is thus pro part in polyurethane formation. However, under certain meted by the co-catalytic action of the tertiary amine and conditions and in the presence of certain catalyst combialdehyde and by acceleration of the reactivity in the sysnations, isocyanate polymerization is sharply accelerated tern due to the increase in temperature from exothermic to make isocyanate polymers quite practical, per se, and polymerization and condensation. i of significant importance in the polyurethane system. The nature of the accelerating reaction is not defined, Accordingly, an object of the present invention is the nor the specific contribution that the aldehydes make to formulation of a catalyst capable of promoting a rapid r the reaction. However, in studying the various compopolymerization of organic isocyanates to polyisocyanates. nents of the reaction it has been found that isocyanates Another object of the present invention is the formulaare readily polymerized by a combination of diazabicyclotion of a catalyst to promote a rapid interaction of diisooctane anda C to C aldehyde, whereas isocyanates and cyanates and polyols to produce stable self-curing flexible diazabicyclooct-ane react very slowly to form isocyanate or rigid, foamed or unfoamed polyurethane resins. polymers and isocyanates are essentially unreactive with Another object of the present invention is the formula- 40 aldehydes. Apparently, the catalytic polymerization of tion of a catalyst particularly effective in the condensa- 'the organic isocyanate and the heat evolved thereby is tion of diisocyanates and hydroxy compounds to form the key to the accelerated formation of either polyisopolyisocyanate modified polyurethanes and polyurethane cyanates or polyurethanes. This is shown in a number modified polyisocyanate resins. These and other objecof examples wherein isocyanates were polymerized in the tives are accomplished as hereinafter described: presence of selected aldehydes and diazabicyclooctane:

EXAMPLE I ls ocyanate polymerization Diazablcyclo- Aldehyde, g. Isoeyanate, g. Minutes to Product octane, g. max. temp.

Butyraldehyde, 32.7""- None. Paraldehyde, 52.2 None. Butyraldehyde, 32.7. Butyraldehyde, 1.6 (Solid 18 hr.).

Furfur o-Anisaldehyde, 56.3. Paraldehyde, 50..-

HeptaldehydeI IWZ Trimer (isocyanurate) Orange syrup (6.5 hr.). None in 3 hr.

. Trimer, 76% yield. Vise. syrup (1 hr.). Thick syrup (1% hr.).

, Slow temp. rise. TDI,* 631 Slow temp. rise.

*TDI=Tolylene diisocyauate; 80/20 of 2,4/2,6 isomer.

In accordance with the present invention, polymerization of organic isocyanates and the formation of urethanes is catalyzed by tertiary amines in combination with C to C aldehydes. More particularly, we have found that 1,4-diazabicyclo-(2,2,2)-octane, as representative of tertiary amine catalysts, in combination with an equi-rnolar to major amount of a C to C aldehyde, such as benzaldehyde, has an unusual and unexpected catalytic effect on organic isocyanates, causing them topolymerize rapidly to polyisocyanates with the release of heat, and on aldehydes, tolylene diisocyanate polymerization to gel form was studied with diazabicyclooctane and various aldehydes at roughly equivalent molar concentrations:

EXAMPLE II T DI polymerization with dlazabzcyclooctane (0.25 g.=.0023 mol) and aldehydes [TDI=61 g.=0.35 mole] Aldehyde or polymer Max. 'Minutes Product aldehyde, g. (moles) temp., to max. description C. temp.

Aeetaldehyde, 2. 4 (.0 72.8 16 Hard yellow solid. Butyraldehyde, 4.55 (053)--" 110 45 Pale yellow solid. 'lrioxymethylene, 1.7 (0.056) 128 67 Yellow solid. Heptaldehyde, 6.33 (.056 53 93 Do. 5 Benzaldehyde, 5.88 (0.055)...- 82 69 Hard yellow solid. Isodecaldehyde, 8.74 (056).-.. 87 128 Yellow solid. (LAnisaldehyde, 7.55 (0.063) 70 242 Pale yellow solid. Paraldehyde, 2.49 (.057) 28 Copious precipitate over-night. l-naphthaldehyde, 8.74 (.056)- Yellow solution V by standing over-night.

T DI polymerization to gel with aldehyde-tertiary amine co-catalysts [TDI:61 g.:0.35 mole] Thus active aldehydes in the C to C range having molecular weights ranging from 30 to about 200 are effective co-catalysts.

The process of isocyanate resin formation can be carried further with additional time at room temperature or with supplementary heating to produce polyisocyanates and aldehyde modified polyisocyanates as hard brittle resins.

With 500 parts of tolylene diisocyanate, 4.5 parts of diazabicyclooctane and 9.0 parts of paraform, mixing these ingredients at room temperature produces a viscous syrup. This intermediate product can be used to imregnate fibers or fabrics, such as glass fabrics, for the production of heat-cured laminates having high tensile strength, flexural strength and heat resistance.

In the presence of both hydroxy compounds and diisoeyanates the co-catalyst combination of aldehyde and tertiary amine is effective in producing new and interesting compositions comprising mixed polyisocyanates and polyurethanes.

EXAMPLE III T Dl-polyol reaction with diazabicyclooctane and trioxymethylene parts of polypropylene glycol, PPG 1025, were put in a reaction vessel,

H 1.0 part of trioxymethylene (formaldehyde polymer) and 0.25 part of diazabicyclooctane were added and the mixture stirred to effect uniform solution.

17.4 parts of tolylene diisocyanate (Hylene TM-Du Pout) were then added with stirring.

t. Amine, moles Aldehyde, moles Product gel time ot- Room temp.

Dlazabieyelooetane, .0005- Diazabieyeloootane, 0 Diazabieyelooetane, .0005.

Butyraldehyde, 0.005 Trioxymethylene, 0.005 Butyraldehyde, 0.005.. Benzaldehyde, 0.005 Cinnamaldehyde, 0.005.. Butyraldehyde, 0.005

66 hr. (ungelled) 60 min.

' On the basis of these experimental evaluations, the activities of the C to C aldehydes generally decreased with increasing molecular weight (with the aldehyde polymers acting as polymers rather than momeric alde- 50 hydes G. mole Acetaldehyde 42 Butyraldehyde 72 Trioxymethylene (calculated as formaldehyde trimer) 90 In four minutes a maximum temperature of 663 C. was

reached.

After 7.5 minutes of reaction time the mixture became more viscous and milky white in color. After 15 minutes the viscous product was split into two portions. In 18 hours at room temperature, one portion became a pale yellow rubbery mass. .The second portion was heated in an oven about 20 minutes at 140 0., taking on the foamy appearance of expanded polyurethane, though Benzaldehyde 106 considerably more dense and rubbery than a typical light Heptaldehyde 114 (2 lb./ sq. ft.) polyurethane foam.

Isodecaldehyde 156 Elastomeric products have been prepared using tolylene Cinnamaldehyde 132 diisocyanate (Hylene TM), polypropylene glycol (PPG o-Anisaldehyde 136 1025 with diazabicyclooctane and typical C to C Paraldehyde (calculated as acetaldehyde trimer) 132 aldehydes as co-catalysts.

EXAMPLE IV TDl-polyol elastomers prepared with diazabicyclooctane and aldehydes Max. temp. Mins. to Aldehyde, g. (moles) of exotherm reach max. Prod. outing at room T. Prod. curing at 100 C.

' oi exotherm (64 hrs.) in glass (64 hrs.) in glass Trioxymethylene, 1.7 (.056) 58 10 Yellow opaque rubbery solid Brownish-white opaque rubbery solid. Par-aldehyde, 2.49 (.057) 65 5 Viscous syrup Rubbery solid. Heptaldehyde, 6.33 (.056) 66 6 Clear yellow transparent Tough yellow-brown rubbery rubbery solid. solid. Benzaldehyde, 5.88 (.055) 57 9 Yellow, very viscous syrup. Rubbery solid. Butyraldehyde, 4.55 (.063) 68 5 Yelllritiv transparent rubbery Yelllriivlsh-brown rubbery S0 S0 o-Anisaldehyde, 7.55 (.063) 66 6 Clear, yellow transparent gel, Yellow-brown somewhat tacky and elastic. tacky rubbery solid.

*Charge=PPG 1025= g.=0.1 mole; Hylene TM=34.8 g.=0.2 mole; diazabieyelooctane=0.25 g.=0.0023 mole.

In each of the above preparations a portion ofthe reaction mixture was removed from the reaction vessel after the maximum exotherm was obtained. These viscous (uncured) syrups were spread on aluminum sheets and cured for 63 hours at room temperature. The resinous films obtained were strongly adherent to aluminum; and the film obtained with benzaldehyde acting as the co-catalyst was especially clear and free of blisters. These resins are promising as new types of elastomers, film forming materials, sealants, metal bonding agents, caulking compounds and adhesives.

Urethane condensation has been eifectively catalyzed with 0.5 part of diazabicyclooctane per 100 parts of hydroxy material (polyol such as PPG 2000, polypropylene glycol approximately 2000 molecular weight), though concentrations of the tertiary amine catalyst may vary from 0.1 to 5 parts per 100 of polyol. To obtain the particular catalytic composition of our invention it has generally been desirable to use at least an equi-molar amount of a C to C aldehyde with diazabicyclooctane. The aldehyde concentration may thus vary from 30 parts of aldehyde to 110 parts of diazabicyclooctane (an equimolar ratio for formaldehyde and diazabicyclooctane), to substantially larger amounts of higher molecular weight aldehydes, e.g., 210 parts of benzaldehyde per part of diazabicyclooctane, or roughly 200 moles of aldehyde per mole of diazabicyclooctane.

In general, the ratio of diisocyanates to polyols is in the range of 30-40 parts per 100 parts respectively. Smaller amounts of diisocyanates may be used with properties of the polymer varying accordingly. In the process of the invention, where isocyanate polymer formation is an important factor in controlling the properties of the polymer product, the ratio of organic isocyanate to polyol is at least 2 to 1 on an equivalent (NCO/ OH) basis, as in Example 111 above, and may be as high as 4 or 6 to 1 where isocyanate polymers are formed and copolymerized with polyurethanes in the process.

Elastomers and dense rubbery foams as described in Example III may be expanded into lighter weight stable foams with supplementary blowing. As is well known in the art, this can be eifected by reacting water with isocyanate in the formulation to form ureide-linked polymers and carbon dioxide. Such foamed products have been made though at relatively high cost in organic isocyanate. To obtain controlled foaming of such polyisocyanate-polyurethane elastomers, the use of 3 to of selected Freons has been found eifective.

EXAMPLE V 100 parts glycerine propoxide triol (11-300), 4000 mol.

wt.-45 OH number 40 parts (TD80) tolylene diisocyanate 0.7 part DABCO (diazabicyclooctane) 10.0 parts trioxymethylene 1.0 part organo-silicoue (D.C. 199) 7.0 parts trichloro-trifluoroethane These ingredients are reacted in the usual way by dissolving the diazabicyclooctane, trioxymethylene and the silicone in water, mixing with polyol and Freon, adding the TDI with mixing and mixing for about to 30 seconds until creaming is noted. The mix is then poured into a coated mold in which the product is foamed to a tough rubbery solid in about 3 to 4 minutes. The product is finished by an oven cure of 2 hours at 150 F. and removed from the mold as a tough foamed polyisocyanate-polyurethane product having a density of about 3 to 5 lb./ft.

Reactions have been described using a combination of diazabicyclooctane and a C to C aldehyde as a catalyst in polymerizing isocyanates, particularly diisocyanates, and in condensing diisocyanates and polyols in a modified urethane reaction. Various modifications in this general area of reaction have been demonstrated and come within the scope of the invention. For example, diisocyanates and diisocyanate polymers retaining excess isocyanate reaction readily with monohydroxy compounds as well as with diols or polyols to form urethane modified polyisocyanates, which are, in themselves, interesting waxy resins. On reacting 1.0 part of trioxymethylene per 51.2 parts of heptadecanol, 34.5 parts of TDI and 0.25 part of diazabicyclooctane, a maximum pot temperature of C. was noted in 20 minutes. A limecolored waxy product was formed overnight which, after 18 hours curing at C. became a clear yellow nonbrittle solid.

The long chain alkyl urethane-modified polyisocyanate thus formed has been described as blocked isocyanate which is appreciably dissociated at higher temperatures of about 80140 C. releasing isocyanates, which are reactive, for example, with polyols in urethane condensation or may polymerize further to more complex polyisocyanates.

-- low temp.

R1 high temp] llow temp.

*Where R is alkyl, alkenyl, or aryl.

EXAMPLE VI Isacyanaie polymerization with benzaldehyde and tertiary amines [61 parts TDI and 5.88 parts benzaldehyde] Wt. parts O. max. temp.

Minutes to max. temp.

Tort. amine Product Diazabicyclooctane- Triethylamine 31 Hard yellow solid.

Yellow transparent solid overnight.

N ,N,N ,N-tetra- 26 Do.

methyl-butanediamine 1,3.

N-methyl morpholine-.

Milky solution some ppt.

Yellow solution some ppt.

Pyridine- *No apprec. temp. change.

The corresponding reactions with tertiary amine but with no aldehyde present produced no hard resins on standing over-night.

Obviously many modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

What is claimed is:

1. The method of preparing polymeric compositions which consists of: preparing a reaction mixture containing tolylene diisocyanate; adding to such reaction mixture a catalyst composition providing, per 100 parts of said reaction mixture, from 0.1 part to 10 parts of a mixture of diazabicyclooctane and C to C aldehyde, there being from 0.01 part to 10 parts of diazabicyclooctane per part of C to C aldehyde; and recovering the polymeric composition resulting from the polymerization of the reaction mixture under the influence of said catalyst composition.

2. The method of preparing polyurethane compositions which consists of: preparing a reaction mixture consisting essentially of tolylene diisocyanate and a polyol composition selected from the group consisting of glycerol propoxide and polypropyleneglycol; adding to such reaction mixture 2. catalyst composition providing, per 100 parts of said reaction mixture, from 0.1 part to 10 parts of a mixture of diazabicyclooctane and C to C aldehyde there being from 0.01 part to 10 parts of diazabicyclooctane per part of C to C aldehyde; and recovering the polyurethane composition resulting from the polymerization of the reaction mixture under the influence of said catalyst composition.

References Cited by the Examiner UNITED STATES PATENTS 2,888,411 5/59 Pace 260-775 2,939,851 6/60 Orchin 260-77.5 2,949,431 8/60 Britain 260-77.5 3,010,963 11/61 Erner 260--77.5 3,087,912 4/63 Wagner 260-775 FOREIGN PATENTS 848,965 9/60 Great Britain.

OTHER REFERENCES Degering: Outline of Organic Nitrogen Compounds,

1950, page 313.

Naming and Indexing of Chemical Compounds, Chemical Abstracts, page 46N, 47N, and 89N, 1962.

LEON J. BERCOVITZ, Primary Examiner.

H. N. BURSTEIN, P. E. MANGAN, DONALD E.

CZAJA, Examiners. 

1. THE METHOD OF PREPARING POLYMERIC COMPOSITIONS WHICH CONSISTS OF: PREPARING A REACTION MIXTURE CONTAINING TOLYLENE DIISOCYANTE; ADDING TO SUCH REACTION MIXTURE A CATALYST COMPOSITION PROVIDING, ER 100 PARTS OF SAID REACTION MIXTURE, FROM 0.1 PART TO 10 PARTS OF A MIXTURE OF DISZABICYCLOOCTANNE AND C1 TO C10 ALDEHYDE, THERE BEING FROM 0.01 PART TO 10 PARTS OF DIAZABICYCLOOCTANE PER PART OF C1 TO C10 ALDEHYDE; AND RECOVERING THE POLYMERIC COMPOSITION RESULTING FROM THE POLYMERIZATION OF THE REACTION MIXTURE UNDER THE INFLUENCE OF SAID CATALYST COMPOSITION. 